Topic 9: Seperate Chemistry 2 Flashcards

1
Q

What is the test for sulfates?

A
  1. Add dilute hydrochloric acid (to remove any carbonate ions that might obscure results) and barium chloride solution to a solution
  2. If sulfate ions are present, a white precipitate of barium sulfate will form
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2
Q

What is the test for chloride?

A
  1. Add nitric acid and silver nitrate solution to a solution
  2. If chloride ions are present, a white precipitate will form of silver chloride
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3
Q

What is the test for bromide?

A
  1. Add nitric acid and silver nitrate solution to a solution
  2. If bromide ions are present, a cream precipitate will form of silver bromide
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4
Q

What is the test for iodide?

A
  1. Add nitric acid and silver nitrate solution to a solution
  2. If iodide ions are present, a yellow precipitate will form of silver iodide
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5
Q

What are the 3 halides you need to know tests for?

A
  1. Chloride
  2. Bromide
  3. Iodide
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6
Q

What is the test for carbonates?

A
  1. Add a couple of drops of a dilute acid to a solution which will fizz if carbonate ions are present
  2. Connect the test tube with the solution to a test tube with limewater
  3. If carbonate ions are present, the limewater will turn milky as carbon dioxide will be formed (and limewater turns cloudy/milky when carbon dioxide is present)
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7
Q

What is the test for metal cations?

A
  1. Add a few drops of sodium hydroxide to a solution
  2. The colour of the precipitate that forms depends on the metal ion in the solution
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8
Q

When testing for metal cations using sodium hydroxide, what colour is the precipitate formed if calcium is present in the solution?

A

White

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9
Q

When testing for metal cations using sodium hydroxide, what colour is the precipitate formed if copper (II) is present in the solution?

A

Blue

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10
Q

When testing for metal cations using sodium hydroxide, what colour is the precipitate formed if iron (II) is present in the solution?

A

Green

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11
Q

When testing for metal cations using sodium hydroxide, what colour is the precipitate formed if iron (III) is present in the solution?

A

Brown

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12
Q

When testing for metal cations using sodium hydroxide, what colour is the precipitate formed if aluminium is present in the solution?

A

White

BUT with excess NaOH, the precipitate re-dissolves to form a colourless solution

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13
Q

What is the test of ammonium ions?

A
  1. Add sodium hydroxide solution to the solution you’re testing and gently heat
  2. If ammonium ions are present, ammonia gas will be given off
  3. Ammonia gas turns damp red litmus paper blue - so that how you can check if ammonium ions are present
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14
Q

What colour does a flame turn in a flame test if calcium ions are present in the sample?

A

Orange-red flame

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15
Q

What colour does a flame turn in a flame test if sodium ions are present in the sample?

A

Yellow flame

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16
Q

What colour does a flame turn in a flame test if potassium ions are present in the sample?

A

Lilac flame

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17
Q

What colour does a flame turn in a flame test if lithium ions are present in the sample?

A

Crimson flame

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18
Q

What colour does a flame turn in a flame test if copper ions are present in the sample?

A

Blue-green flame

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19
Q

Disadvantages of flame tests?

A

If the sample contains a mixture of metal ions, the flame colours of some ions may be hidden by the colours of other - may not give you the correct results

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20
Q

What is instrumental analysis?

A

Tests that use machines

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21
Q

3 advantages of instrumental analysis?

A
  1. Sensitive - can detect even the tiniest amounts of ions
  2. Fast - tests can be automated
  3. Accurate - don’t involve human error
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22
Q

What are 2 uses of flame photometry?

A
  1. Identifying ions in solution
  2. Determining the concentration of ions
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23
Q

How does flame photometry identify ions in a solution?

A

Each ions produces a unique line spectrum - allows you to compare with a reference spectra

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24
Q

How can flame photometry determine the concentration of ions?

A

The intensity of the lines on the spectrum can allow this to be calculated:
1. Find the intensity that’s been measured on the graph
2. Correspond this to the concentration using the calibration curve (line on the graph)

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25
Q

What is flame photometry an example of?

A

Instrumental analysis

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26
Q

If multiple ions are present in the sample in flame photometry, what happens to the spectrum?

A

The spectrum will be a combination of all of the ions’s individual spectra

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27
Q

What are alkanes?

A

The simplest type of hydrocarbons, containing only single covalent bonds

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28
Q

What is the general formula for alkanes?

A

CnH2n+2

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29
Q

Are alkanes saturated or unsaturated? Why?

A

They’re saturated - all the atoms have formed single covalent bonds with as many other atoms as possible

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30
Q

What are the first 4 alkanes in the alkane homologous series? WITH FORMULAS

A

Methane CH4
Ethane C2H6
Propane C3H8
Butane C4H10

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31
Q

How to remember the order of the first 4 compounds in all hydrocarbon homologous series?

A

Monkeys
Eat
Pink
Bananas

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32
Q

What is an alkene?

A

Hydrocarbons that have one C=C double bond functional group

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33
Q

What is a functional group?

A

A group of atoms in a molecule that dictate how that molecule typically reacts

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34
Q

Are alkenes saturated or unsaturated? Why?

A

Unsaturated - the double bind can open up to form other bonds

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35
Q

What are the first 3 alkenes in the alkene homologous series? WITH FORMULAS

A

Ethene C2H4
Propene C3H6
Butene C4H8

NO METHENE BECAUSE AN ALKENE NEEDS TO HAVE AT LEAST 2 CARBONS TO HAVE A CARBON DOUBLE BOND AND METHENE WOULD ONLY HAVE 1 CARBON MOLECULE

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36
Q

What can happen to the double bond in alkenes in addition reactions?

A

It opens up - another substance adds across the double C=C bond

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37
Q

What is the test for alkenes?

A
  1. Add solution to bromine water
  2. Shake the mixture
  3. If the mixture turns colourless, alkene is present
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38
Q

If an alkane is added to bromine water, what happens?

A

Nothing - the bromine water remains orange (doesn’t turn colourless like it does for alkenes)

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39
Q

What is the equation for combustion of hydrocarbons?

A

Hydrocarbon + oxygen —> carbon dioxide + water

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40
Q

What are polymers?

A

Substances made by joining lots of small repeating units (monomers), they have a high average Mr

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41
Q

What is addition polymerisation?

A

When molecules with C=C bonds join together in addition reactions

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42
Q

Describe the process of addition polymerisation?

A
  1. A monomer (e.g. ethene) will open up its carbon double bond
  2. This will then allow the same monomers to join up to each other and form a polymer (e.g. poly(ethene))
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43
Q

What are polymers named after?

A

The monomers that they’re formed from

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44
Q

Describe the steps of drawing the displayed formula of a polymer from its monomer

A
  1. Draw the alkene carbons and replace the double bond with a single bond
  2. Add an extra single bond to each carbon atom
  3. Add the other groups in the same way that they surround where the double bond was
  4. Add brackets and an ‘n’ at the bottom
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45
Q

What are the properties of poly(ethene)?

A

Flexible
Cheap
Electrical insulator

46
Q

What are the uses of poly(ethene)?

A

Carrier bags
Wire insulation

47
Q

What are the properties of poly(propene)?

A

Flexible
Strong
Tough
Mouldable

48
Q

What are the uses of poly(propene)?

A

Plastic crates
Ropes

49
Q

What are the properties of poly(chloroethene)?

A

Tough
Cheap

50
Q

What are the uses of poly(chloroethene)?

A

Window frames
Water pipes

51
Q

What is poly(chloroethene) also known as?

A

PVC

52
Q

What are the properties of poly(tetrafluoroethene)?

A

Unreactive
Tough
Non stick

53
Q

What are the uses of poly(tetrafluoroethene)?

A

Non stick pans
Waterproof clothing

54
Q

What is poly(tetrafluoroethene) also known as?

A

PTFE

55
Q

What is condensation polymerisation?

A

Polymers formed from monomers with two functional groups where a by product of the polymerisation is water

56
Q

What is the equation for condensation polymerisation?

A

Diol + dicarboxylic acid —> polyester + water

57
Q

What are 3 natural polymers?

A
  1. DNA
  2. Starch
  3. Proteins
58
Q

What is DNA?

A

A complex molecule that contains genetic material

59
Q

What is the monomer that forms DNA?

A

Nucleotides

60
Q

What is starch?

A

A polymer made from sugars

61
Q

What is the monomer that forms starch?

A

Sugars

62
Q

What are proteins?

A

Condensation polymers of amino acids

63
Q

What is the monomer that makes proteins?

A

Amino acids

64
Q

What are the uses of protein in the body?

A

Are in enzymes

65
Q

Advantages of recycling plastics?

A

Less plastics have to be disposed of - results in less non biodegradable waste going to landfill & also in less carbon dioxide and toxic gases being related by burning plastics
Generally uses less resources than making new plastics - made from crude oil (finite resource)
Generally saves money and creates jobs

66
Q

Disadvantages of recycling plastics?

A

Must be separated before melting down - difficult and expensive
Melting down can still release polluting gases
Over time, strength of polymer decreases - can’t recycle the same polymer forever

67
Q

What is an alcohol?

A

A compound containing -OH functional group

68
Q

How can alkenes be made from alcohols?

A

Heating alcohol with an acid a catalyst - this is a dehydration reaction as a molecule of water is lost from the alcohol

69
Q

What are the names of the first 4 alcohols in the alcohol homologous series? WITH FORMULA

A

Methanol CH3OH
Ethanol C2H5OH
Propanol C3H7OH
Butanol C4H9OH

70
Q

What is the the general formula for alcohols?

A

CnH2n+1OH

71
Q

What is a Carboxylic acid?

A

A compound containing a -COOH functional group

72
Q

What do Carboxylic acids have the same properties as?

A

Weak acid solutions

73
Q

How can Carboxylic acids be made from alcohols?

A

If alcohols are oxidised - e.g. ethanol can be oxidised to form ethanoic acid

74
Q

Why do members of a homologous series have similar reactions?

A

They have the same functional group

75
Q

What are the names of the first 4 Carboxylic acids in the Carboxylic acid homologous series? WITH FORMULA

A

Methanoic acid HCOOH
Ethanoic acid CH3COOH
Propanoic acid C2H5COOH
Butanoic acid C3H7COOH

76
Q

What is fermentation?

A

Process where a yeast enzyme converts solutions of carbohydrates (e.g. sugars) into alcohol

77
Q

What is the equation for fermentation?

A

Sugar —yeast—> ethanol + carbon dioxide

78
Q

What are the optimum conditions for fermentation?

A

30-40 °C
Anaerobic conditions

79
Q

Why does fermentation only produce a dilute solution of ethanol?

A

Yeast dies when concentration is too high

80
Q

What is the use of fractional distillation after fermentation?

A

Used to concentrate the ethanol solution

81
Q

Describe the process of fractional distillation after fermentation

A
  1. Dilute ethanol is heated using a Bunsen burner
  2. Ethanol will boil before the water
  3. A Liebig condenser will then condense the ethanol and will produce a concentrated version of the ethanol
82
Q

What is the diameter in nm (size) of atoms and simple molecules?

A

0.1 - 1 nm

83
Q

What is the diameter in nm (size) of nanoparticles?

A

1 - 100 nm

84
Q

What do nanoparticles contain?

A

A few hundred atoms

85
Q

How to calculate surface area to volume ratio?

A

Surface area to volume ratio = surface area/volume

86
Q

Do nanoparticles have a high or low surface area to volume ratio?

A

They have a high surface area to volume ratio compared to larger particles - gives them different properties to bulk materials

87
Q

What are the 3 uses of nanoparticles? Why?

A
  1. Catalysts - more surface area means faster rate of reaction
  2. Medicines - small particles could be absorbed right into target cells
  3. Cosmetics e.g. sunscreen - small particles provide more protection and don’t leave marks on skin & prevent uv rays from reaching skin
88
Q

What are the downsides of using nanoparticles as cosmetics or medicines?

A

They can have harmful effects on health e.g. nanoparticles could build up in cells over time if they don’t get broken down

89
Q

What are properties of polymers?

A

Thermal and electrical insulators
Often flexible, can be moulded
Lower density than metals and ceramics

90
Q

What are uses of polymers?

A

Electrical casing
Carrier bags and squeezy bottles

91
Q

What are the 2 types of ceramics?

A
  1. Clay
  2. Glass
92
Q

What is a clay ceramic?

A

Soft mineral hardened by firing

93
Q

What is an example of a glass ceramic?

A

Soda lime glass made by heating limestone, sand and sodium carbonate

94
Q

What are properties of ceramics?

A

Can be moulded and shaped
Strong
Brittle
Glass is transparent

95
Q

What are the uses of clay ceramics?

A

Bricks
Pottery

96
Q

What are the uses of glass ceramics?

A

Glassware

97
Q

What are composites?

A

One material embedded into another

98
Q

What are the properties of composites?

A

Depends on the material used

E.g. concrete is strong and dense
E.g. carbon fibre is strong and light

99
Q

What is the use of the composite material concrete?

A

Buildings

100
Q

What is the use of the composite material carbon fibre?

A

Sports cars

101
Q

What are properties of metals?

A

Thermal and electrical conductors
Malleable

102
Q

What are the uses of metals?

A

Wiring

103
Q

What are nanoparticles?

A

A nanoparticle is a piece of a material consisting of a few hundred atoms, and between 1 nm and 100 nm in size

104
Q

What is a material made of nanoparticles called?

A

A nanoparticulate

105
Q

Describe how you would carry out a flame test to test for ions

A
  1. Clean a nichrome wire using hydrochloric acid
  2. Turn the Bunsen burner onto the blue flame
  3. Dip the wire in a solution of the substance being tested
  4. Place the wire in the flame and record the colour
106
Q

Why must the wire be cleaned before carrying out a flame test?

A

To remove any unwanted ions that might obscure the colour of the flame

107
Q

How could you distinguish between two solutions containing aluminium ions and calcium ions?

A

Add excess sodium hydroxide - both will form white precipitates initially BUT the precipitate formed from aluminium ions will re-dissolve to form a colourless solution

108
Q

What is a flame photometer?

A

A device used in inorganic analysis - can be used to identify or determine the concentration of metal ions

109
Q

What is the major advantage of flame photometry compared to simple flame testing?

A

Flame photometry can be used to analyse a mixture of ions whereas flame tests can only be used to identify one ion at a time

110
Q

How do you carry out tests for halide ions?

A
  1. Add a few drops of nitric acid to react with any carbonate ions which might obscure the result
  2. Add a couple of drops of silver nitrate
  3. Observe the colour of the precipitate
111
Q

What are the 6 cations we need to know tests for?

A
  1. Ammonium
  2. Copper (II)
  3. Iron (II)
  4. Iron (III)
  5. Aluminium
  6. Calcium